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Transmission Options

I ended up going with a 2008 RX8 S2 gearbox as it was stronger than the S1 gearbox and newer and cheaper than an RX7S5 turbo box. I considered the gearbox form an RX7 FD but they have a pull style clutch which would mean I couldn't use my existing clutch. The choice of the RX8 gearbox came down to availability, cost and the fact I could use my existing clutch.

I think I'll need to change the Diff Ratio from 3.27 to 4.11 to make the gearbox more usable, below is a simulation with a 4.11 Diff and the RX8 Gear ratios shifting at 8000rpm with 15inch tyres.


Some of the options
Jatco 3 speed automatic box including torque converter $7,000

JK40C/CD transmission from 350/370Z

Adapter kits:


they all seem to need:
Does Not include (but requires) the following:
T56 Slave Cylinder (throwout bearing)
13B REW Automatic bell housing
FC FD Counter Weight
FD Automatic Flexplate (required if you do not select the Billet flywheel)
FD Automatic Starter
FD Automatic Counter-weight
Automatic Rear housing is required.

Which seem like a lot of work.

Tremec TKO Transmissions:



Tremec TKO to Rotary Adapter
CNC machined billet alloy adapter. Allows 13B turbo bell housings to be bolted to Tremec TKO transmisions. Two adapters available - one to suit FC (S4/5) bell housings, and one to Suit FD (S6-8) bell housings. In both caes the existing 13B turbo clutch/flywheel/starter is all retained - only the clutch spline must be changed to suit. Fitting instructions included.

Green Brothers racing offers a steel bell housing to adopt a TKO, $1,200

Steel Bell Housing - Tremec TKO to Rotary
This bellhousing is built to NZDRA and ANDRA specifications from cold rolled 6mm steel and laser cut 10mm flanges. Approx weight 10kg. Designed to be used with hydraulic release bearing. Bolts up to 12A, 13B and 20B. No scatter shield or blanket required. No adapter required, bellhousing bolts directly to the TKO gearbox (minor modification to TKO case is required to clear starter motor). Bell housing is designed to suit 320mm ring gears, and uses a S4/5 13B turbo starter. Photo is a sample only.



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